Term: Strainer

A strainer is a rigid frame over which a painting canvas is stretched to make a support. The frame is usually made with wooden members that have tongue-and-groove ends that are fixed. These corners are secured with nails, screws, dowels, glue, pegs, or other types of hardware. A stretcher is very similar to a strainer but a stretcher has expandable corners. For this reason, it can be expanded to tighten a loose canvas even after the canvas has been attached. The straightness and strength of the wooden stretcher bars determine how flat and taut the final painting will be.